Media-centric companies are often interested in tracking how often and/or how long audience members are exposed to media compositions (e.g., television programs, motion pictures, internet videos, radio programs, etc.). To obtain exposure information, some techniques include generating signatures (e.g., representations of some, preferably unique, portion of the media composition or the signal used to transport the media composition) or embedding identification codes (e.g., watermarks) that are then detected at a time of exposure (e.g., during a television viewing session).
Other techniques include active audience member participation. In one example exposure detection system, audience members (e.g., members of a household) are given surveys to be completed at the end of a week to indicate which television and/or radio stations to which they were exposed during the week.